[cathoderay57]

Hi Steve, when you switch off and on you say the volume and sensitivity increase. Do they stay that way, or does the sound fade back down to the previous level after a second or two? Rapidly re-applying power will cause a surge that can sometimes have strange effects, sometimes harmful particularly to a possibly tired old rectifier valve or HT smoothing capacitor and so I recommend you don't demonstrate it too often. It would be helpful to measure dc voltages on the cathode of the rectifier and the anodes and screen grids (Grid 2) of the valves in the steady-state condition. You should be able to compare these with the values quoted in the Trader sheet. If you are using a digital voltmeter then expect your measurements to read higher than the Trader. Cheers, Jerry